We propose to enhance our training program for MD investigators in epidemiology of infectious diseases, emphasizing clinical, rather than observational, epidemiology. Because our faculty is relatively small, we will focus on areas of strength: microbial ecology, vaccine preventable diseases, HIV, and tuberculosis. These four domains provide exemplars for training in disease emergence, prevention, control and treatment. All trainees are required to obtain either a Masters degree in Clinical Epidemiology with in-depth training in epidemiologic methods, biostatistics, and infectious diseases epidemiology, or in Health Services Research with an emphasis on vaccine and disease modeling and outcomes research. Fellows can optionally receive training in other areas such as environmental microbiology and medical informatics. The program will be interdisciplinary, involving faculty from the three schools (Medicine, Humanities and Sciences, and Engineering) two Centers (Freeman Spogli Institute for International Studies and Woods Institute for the Environment), and seven Departments (Medicine, Pediatrics, Pathology, Health Research and Policy, Civil and Environmental Engineering, Management Sciences and Engineering, and Anthropology). Additionally, we plan to continue to foster our strong alliances in epidemiology with the local county health department. Trainees will be drawn from the pool of candidates for the infectious diseases post-doctoral fellowship programs in pediatrics and internal medicine; exceptional applicants from other clinical post-doctoral programs at Stanford may be considered if they have demonstrated prior commitment to epidemiologic research in emerging Infections or bioterrorism. Accepted trainees will conduct research under the mentorship of at least two training program faculty members-a research mentor and a methodologic mentor. Research projects are expected to be cross-disciplinary to take advantages of the breadth of campus faculty. To promote interaction among trainees and faculty, research seminars conducted by trainees, interdisciplinary seminars in infectious diseases epidemiology, weekly infectious diseases grand rounds, infectious diseases, ecology and bioterrorism lectures presented by faculty and an annual 1-day research retreat will be held. Each trainee will be counseled and directed by a Research Committee comprised of the mentor and others whose area of expertise is relevant to the project. Two MD post-doctoral trainees are to be supported by the Training program each year. All trainees will be strongly encouraged to apply for independent support. Trainees are expected to move on to academic or public health leadership positions. RELEVANCE (See instructions): Emerging infectious diseases-including naturally occurring and man-made pathogens-represent an ongoing threat to human populations worldwide. Through our training program, we will create physician investigators with skills and knowledge to prevent, control and treat these challenges to human health.